In many industrial and commercial processes it is highly desirable to have a temperature profile of a component as it moves through the process, or a part of the process. This information can be very useful in optimizing the quality and uniformity of the process treatments, minimizing energy consumption, and locating potential trouble spots in the process. In the context of the invention, the temperature profile is the record of the changing temperature of a single spot on a component such as a moving fabric.
The determination of an accurate temperature profile is especially useful in the textile industry in general, and particularly in textile fabric heat-setting and drying. In the treatment of fabric webs in conventional drying and heat-setting ovens, the oven temperature is commonly set at a predetermined level based on the operator's past experience and only after problems develop, whether they are overheating, underheating, or side-to-side variation, is a correction made in oven temperature, etc. Little assurance of the correct operating condition appropriate for a required time and temperature profile is provided. Because of this, various proposals and techniques have been tried with a view toward obtaining an accurate temperature profile, i.e., temperature history.
One proposed technique for obtaining a fabric temperature profile is to mount a temperature sensor together with electronic processor and memory device on the moving fabric web as it moves through the oven. This system stores and records a temperature profile of the fabric as it rides along through the oven with the fabric. Such a system is not practical, however, due to the expense of selecting appropriate components that can withstand the oven temperatures while passing through the oven, the large mass of the system, and the high cost of replacement when a sensor is damaged.
A further proposal, adapted for use in baking ovens, is to insert a probe into the article being baked and send the probe, along with other components which together form a transmitter, through the oven. The signal from the moving transmitter is beamed out of the oven to a stationary receiver which then receives and interprets the signal. Transistors are noted to be present in at least two of the components utilized. Since the temperature of the oven is normally above the maximum operating temperature of any normally available transistors, the unit is encased in heat insulating material and surrounded by a further enclosure containing solid carbon dioxide. Such an arrangement is impractical since the cooling source must be continuously replenished. Additionally, the temperature probe provided for such a system is not readily adaptable for use with a fabric web, and the components of the system are relatively complicated and expensive.
According to the present invention, a method and apparatus have been provided that overcome the drawbacks inherent in the prior art, as exemplified by the prior art mentioned above. The apparatus according to the present invention is simple, inexpensive, and easy to use. While the apparatus is particularly adapted for use in temperature profiling of moving fabric webs, it also has applicability to other temperature profiling systems wherein the temperature profile of a moving substrate or web is desired. The apparatus according to the present invention is capable of simply and accurately determining the temperature profile of a fabric web in a drying or heat-setting oven or the like without requiring interruption of the fabric processing. It is to be understood that the term "oven" as used herein is meant to include only those ovens where the progress of goods or components through them is along substantially straight and usually horizontal paths, as in a textile tenter oven. With the knowledge of a continuous temperature profile obtained by utilizing the present method and apparatus, the drying, curing, and heat-setting processes can be optimized, allowing the operator to control the process for optimum time and temperature history. Fabric quality and uniformity of treatment are improved, energy consumption is minimized, production capacity is maximized, and potential trouble spots are located, allowing breakdowns to be prevented.
According to the method of the present invention, a temperature profile of a moving fabric web in a textile treating assembly (e.g., drying or heat-setting tenter oven) is obtained utilizing a temperature sensing probe interconnected by a reeled wire to a monitor. Without arresting of the fabric web movement, the temperature sensing probe--with wire attached--is placed in operative engagement with a specific point of the fabric web, the probe maintaining contact with the point of the web and moving therewith into the entrance of the textile treating assembly. The probe is mounted on a structure having fabric engaging and penetrating sharpened pins so that when the probe supporting structure is merely laid on the moving web the pins penetrate and engage the web while the probe is held in contact therewith. Unreeling of the wire is effected as the probe moves with the fabric web through the textile treating assembly, and the temperature of the specific point of the fabric web is continuously measured by monitoring the temperature data supplied by the probe. Desirably the temperature data are continuously recorded, with the data used immediately or subsequently to effect correction of operational parameters associated with the textile treating assembly. Without the fabric web movement being arrested the probe is disconnected from the web after it exits the textile treating assembly, and the wire is reeled up. Between the disconnection and reeling steps, preferably the wire is disconnected from the probe so that the wire alone is pulled back through the textile treating assembly while the probe, and its mounting structure, are carried back to the assembly entrance. The reel rotates about an axis to let out the take up the wire while making continuous electrical contact between the wire and the monitor during wire let out and take up, and wire take up may be effected by manually rotating the reel about its axis of rotation and effecting level wind of the wire. If desired, means may instead be provided for winding up the wire with a small electric or the like motor. The word "wire" as used herein is inclusive of the combinations of two or more separate wires or leads comprising or connected to thermocouples, thermistors, resistance thermometers, or the like, as will be obvious to one of ordinary skill in the field of the invention.
According to one aspect of the apparatus of the present invention, a temperature profiler for a moving substrate is provided. The profiler includes as the two major components a means for engaging the substrate, and a means ensuring transmission of the temperature information from the substrate-engaging means to a useful point. Both such means are in themselves unique.
The means for engaging the substrate to move therewith and determine the temperature of a predetermined point thereon includes a support, a contactor mounted to the support, a temperature probe, and a release electrical connector. In the preferred embodiment wherein the temperature profile of a fabric web is determined, the substrate contactor includes at least one sharpened fabric-penetrating pin mounted on the underside of the support. The temperature probe, which preferably comprises a thermocouple, is mounted to the support to extend into operative relationship with the substrate. A handle is preferably provided mounted to the top of the support to allow ready retrieval of the probe from the moving substrate once it traverses its predetermined path, although an automatic removal mechanism may be utilized instead.
The structure utilized for transmitting the temperature data from the probe to a suitable monitoring point includes a wire reel, an elongated electrically conductive wire, means for mounting the reel for rotation about an axis while providing electrical continuity between the wire and an electrically conductive member stationary with respect to the reel, and means for connecting the stationary electrically conductive member to a monitoring device, such as a recorder. The wire is wrapped around the periphery of the reel and an electrical connector, compatible with the releasable connector at the substrate-engaging means, is mounted on one end thereof. The operator holds a handle extending from the reel and not rotatable therewith to support the reel at the entrance to the traversal path of the substrate. Level winding and unwinding of the wire is controlled by an extension arm, level with mechanism, and wire controlling arms biased into contact with the wire around the periphery of the reel. The operator can manually rotate the reel about its axis to effect winding of the wire back onto the reel.
It is the primary object of the present invention to provide a method and apparatus for simply and effectively obtaining a temperature profile of a moving fabric web. This and other objects of the invention will become clear from the detailed description of the invention, and from the appended claims.